1. Field of the Invention
The present invention relates to a verification apparatus and a verification method for verifying a recording medium on which a picture whose state changes under various conditions is formed, by use of an optical material such as, for example, a hologram and a diffraction grating.
2. Description of the Related Art
In recent years, as recording media (printed matters) requiring high reliability such as ID cards, certificates, or securities, recording media on which a picture is formed by use of an optical material such as, for example, a hologram and a diffraction grating in order to prevent forgery, have been increasing. With respect to a picture formed on such a recording medium as described above, a state thereof changes in accordance with an observational environment. Therefore, conventionally, it is checked with human eyes whether the quality of a picture on a recording medium as described above is appropriate.
Conventionally, as a verification apparatus for recording media as described above, in Japanese Patent No. 2728205 or Jpn. Pat. Appln. KOKAI Publication No. 2002-221496, there is disclosed an apparatus which acquires a picture of the recording medium at a specific position in a state in which light is irradiated on a recording medium from a specific direction, and which makes an operator check the acquired picture. However, by the technology disclosed in the Japanese Patent No. 2728205 or the Jpn. Pat. Appln. KOKAI Publication No. 2002-221496, it is difficult to check the quality while detecting a variation in a picture on a recording medium which changes under various conditions.
Further, in Jpn. Pat. Appln. KOKAI Publication No. 2003-254910, there is disclosed an apparatus which is capable of arbitrarily setting an illuminating direction with respect to a recording medium, a direction in which a picture from a recording medium is acquired, or the like. Further in Jpn. Pat. Appln. KOKAI Publication No. 2003-254910, a picture that a recording medium is photographed under specific conditions and a picture to be a reference are displayed. In accordance therewith, in Jpn. Pat. Appln. KOKAI Publication No. 2003-254910, an operator is made to check the picture of the recording medium. However, in Jpn. Pat. Appln. KOKAI Publication No. 2003-254910, a picture acquired from a recording medium under specific conditions and a reference picture are merely compared with one another with human eyes. Therefore, in the Jpn. Pat. Appln. KOKAI Publication No. 2003-254910, there are problems in time required for verification and verification accuracy.